Patients without pre-existing diabetes who experience in-hospital glycaemia are at increased risk of infection, acute kidney injury and stroke during their stay, Australian data reveal.

With the evidence indicating this is a causal relationship, the findings underscore how hyperglycaemia in hospitals can be used to identify patients – with and without diabetes – at increased risk of adverse outcomes, the researchers say.

The data was derived from the 26-week prospective Diabetes IN-hospital: Glucose and Outcomes (DINGO) study conducted at Royal Melbourne Hospital, Australia’s only hospital with networked blood glucose monitors across all inpatient wards.

Using this technology, researchers collected clinical and glucose data up to the 14^th day of admission in 2558 randomly selected patients, with the sole exclusion criteria being length of stay <24 hours and HbA1c >12.0% to maintain the positivity assumption.

Of those included, 1147 (45%) experienced hyperglycaemia in hospital, a group more likely to be male, more comorbid, have pre-existing diabetes and have higher HbA1c than those without hyperglycaemia.

But even with adjustment for these and other covariables such as age and length-of-stay, the group was at higher risk of three adverse outcomes, the researchers reported in The Journal of Clinical Endocrinology & Metabolism (link here).

These included a 3% increased risk hospital-acquired infection, a 7% increased risk for acute kidney injury and 5% increased risk for stroke, they said.

On the other hand, no association was found for either ACS or mortality after statistical adjustment, although the raw figures did show these occurred with higher frequency in the hyperglycaemia group.

“The DINGO study establishes the importance of evaluating inpatient glycaemia across an entire hospital stay in relation to adverse in-hospital outcomes, beyond the first glucose taken at presentation, to better direct care and quantify morbidity and mortality risk,” the authors wrote.

“This study confirms the prognostic relevance of inpatient hyperglycaemia for adverse clinical outcomes in all hospital inpatients irrespective of pre-existing diabetes status.”

“We provide strong evidence that hospitals and health professional teams should concentrate on the presence of hyperglycaemia in hospital to identify patients with and without diabetes at increased risk of adverse outcomes.”

The study design also enabled the researchers to find some evidence of causality, through both propensity weighting to simulate a clinical trial study design and restriction of glucose data to periods prior to the outcomes of interest.

The authors noted a pathophysiologic relationship between hyperglycaemia and increased infection was already well-established, with hyperglycaemia known to have wide-ranging suppressant effects upon immune functions.

“Specific mechanisms include impaired cytokine production, pathogen recognitions, neutrophil function, and macrophage function,” they wrote.

“Similarly, acute hyperglycaemia is mechanistically linked to acute kidney injury through increased renal oxidative stress, inflammatory cytokine production, endothelial dysfunction, and decreased intravascular blood volume related to osmotic diuresis.”

As a result, they said further intervention studies were warranted in people with and without diabetes to determine means for reducing adverse events.